1. Field
Embodiments of the present disclosure relate to a robot cleaner with an improved travel performance and a control method thereof.
2. Description of the Related Art
In general, a robot cleaner is a device that automatically cleans a region desired to be cleaned without a user's manipulation by sucking up foreign substances such as dust from floors while autonomously travelling in the region.
Such a robot cleaner has a pair of driving wheels installed in both sides of a lower part of its main body and includes one or more casters needed to support the main body in order to turn or move the main body forward or backward in a cleaning region. There are obstacles such as an edge protrusion (a door sill), an object having an inclined surface, and furniture in the cleaning region in which the robot cleaner travels.
A robot having a low main body, such as a robot cleaner, may be caught at an upper portion when entering a narrow gap of an obstacle (e.g., going below a bed or couch), and may be lifted at a driving wheel while the robot cleaner crosses over an obstacle (e.g., a structure or groove in a floor). That is, the robot cleaner may be stuck and immobile.
When only one wheel is in contact with the floor because the robot cleaner is lifted, a conventional robot cleaner applies a suspension that uses a spring to allow a floating wheel, that is, an idling wheel, to protrude in order to secure a frictional force.
However, since the related art robot cleaner depends on the force of the spring, the robot cleaner cannot obtain a sufficient frictional force when its wheel is lifted. In addition, since the wheel is lifted high irrespective of the height of the obstacle, a wheel mechanism such as a gear may be damaged by an external shock (e.g., which is caused by a pet or an object drop) or a shock caused by autonomous vibration when the robot cleaner crosses over the obstacle. Furthermore, since the robot cleaner crosses over the obstacle while its wheel is inappropriately lifted high, the robot cleaner may be rattled and also cannot travel naturally.